The present invention relates generally to heat exchanger furnaces and more particularly to an improved heat exchanger furnace including features which improve its operating efficiency.
Heat exchanger furnaces have previously been constructed wherein a generally cylindrical heat exchanger housing is surrounded by a larger plenum housing to define a plenum chamber between them. Heat transfer occurred almost exclusively by conduction of heat from the heat exchanger housing sidewall to air passing through the plenum chamber. Hot combustion gases were simply vented directly to the atmosphere from the heat exchanger housing thereby wasting considerable energy. Furthermore, it was difficult to control the combustion within the fireboxes of some units with the result that only partially burned fuel had to be removed from the firebox and wasted. Finally, some heat exchanger furnaces have the problem of smoke escaping from the firebox through the fuel supply passage whereby the stored fuel may take on a burnt odor and become less suitable for combustion. These and other problems are believed to be resolved by the heat exchanger furnace of the present invention.